It is known to secure a fire-fighting device under the fuselage of the helicopter, the device comprising a water storage tank fitted with hatches that can be opened to release the water stored in the tank. Such devices suffer in particular from the drawback of reducing the ground clearance of the helicopter, and of presenting storage capacity that is small.
International application WO 2005/014394 describes a helicopter fitted with tanks and a fire nozzle which are disposed inside the fuselage.
U.S. Pat. No. 3,603,506 describes a device for use in flight to spray a chemical contained in a flexible bag that can be releasably installed inside an aircraft; the bag is held in place by a net.
French patent application FR 2 829 103 describes a removable device for storing water inside the cockpit of an aircraft, comprising a flexible tank, a water discharge hatch, and actuators bearing against the tank and serving to expel the water through the hatch.
In general, it has been found that aircraft fitted with a tank in a cabin are difficult to use for any purpose other than fire fighting because of the time and expense involved in installing and removing the on-board fire-fighting system.